SXI: a telescope with a wide field of view microchannel plate optic and CCD detector at the focal plane. The SXI will observe the location, shape and motion of the dayside magnetospheric boundaries. X-rays in the Earth's exopshere result from the solar wind charge exchange interaction between ions in the solar wind and neutrals such as hydrogen in the exosphere and interplanetary space. PI: Steve Sembay, University of Leicester, UK.

UVI: a wide field of view optic sensitive to the Lyman-Birge-Hopffman band of ultraviolet radiation. Filters and coatings will be used to suppress day glow. The UVI will observe the polar cap, and measure the location and width of the auroral oval. It will also observe transient and localised brightenings that occur on the auroral oval edges. PI: Eric Donovan, University of Calgary, Canada.

LIA: a wide field of view proton and alpha particle analyser. This will determine the basic moments of the solar wind ion distributions, such as velocity, density, temperature and the heat flux vector. These measurements, taken simultaneously with the UV and X-ray images, obviate the concerns of arrival times and spatial extents when external solar wind monitors at the distant Langrangian Point L1 are used. The LIA will include a top-hat-type electrostatic analyser. The centre plane of the field of view will be parallel to the ecliptic, to ensure that the solar wind and average plasma sheet flow directions remain within the field of view. Larger dynamic range will be obtained using a variable geometric factor system. PI: Lei Dai, National Space Science Center, Chinese Academy of Sciences, China.